The invention is based on a housing for an air flow rate meter to a mixture-compressing internal combustion engine with externally supplied ignition. A housing for an air flow rate meter is already known (German Offenlegungsschrift 31 03 170), which along with a second housing part in which a throttle device is disposed forms a throttle valve neck for mixture-compressing internal combustion engines with externally supplied ignition; the housing for the air flow rate meter is embodied as a Venturi nozzle. An air bypass line begins upstream of the Venturi nozzle and discharges into the narrowest cross section of the Venturi nozzle, and the air flow rate meter is disposed in that line. The mechanical coupling of the two housing parts in the prior art is typically in the form of a screw connection, as shown for instance in European Patent Application EP 00 96 842 Al. The use of screws and nuts represents considerable expenditure for material. Moreover, the various operations that are required result in a long assembly time, entailing high production costs.
During operation, the danger exists that the screw fastening will loosen unintentionally as a result of the dynamic strains in the form of vibration and impact originating in the engine; the functional capability of the air flow rate meter is impaired thereby. For instance, the engine power can be reduced quite considerably from infiltrated air that is aspirated through leaking portions of the connection between the two housing parts, these leaks being caused by loosening of the fastening screws.
To assure operational safety, other, cost intensive provisions such as spring rings, which adequately secure the screw fastening, are necessary.